Docker Security Hardening

Help me secure my Docker containers and images.

Current setup:
- Base images used: [list images]
- Registry: [DockerHub/private registry]
- Runtime: [Docker/containerd/CRI-O]
- Orchestrator: [Docker Swarm/Kubernetes/standalone]

Security requirements:
1. Image security
   - Minimal base images
   - No root user
   - Read-only filesystem
   - Vulnerability scanning

2. Build security
   - Multi-stage builds
   - Secret handling in builds
   - Image signing
   - SBOM generation

3. Runtime security
   - Resource limits
   - Capability dropping
   - Seccomp profiles
   - AppArmor/SELinux
   - Network policies

4. Registry security
   - Image scanning
   - Admission policies
   - Content trust

Please provide secure Dockerfile templates and runtime configurations.